The present invention relates to injection molding devices and, more particularly, for injection molding devices used in continuous production of plastic preforms.
A typical device for the manufacture of preforms to be used in blow molding plastic carbonated beverage bottles is shown in Gaiser et al. U.S. Pat. No. 4,412,806 and includes an array of male mold components or cores, each having a cylindrical shape, and a corresponding array of female mold components or cavities which receive the cores and together with the cores form the preform mold. The cavities are mounted to the injection molding apparatus and are received within a cavity module having cooling channels so that, subsequent to the injection step of the process, the cores are rapidly cooled to stabilize the preforms. A typical cavity module design is shown in Gaiser et al. U.S. Pat. No. 4,395,222.
Once the injection molding and cooling/stabilization steps are completed, the cores are withdrawn from the cavities and the now stabilized preforms are ejected from the cores simultaneously. Typically, each core assembly includes a pair of reciprocating, pivotal jaws which form a portion of the female cavity, typically the threaded neck portion of the preform. The jaws are displaced relative to the cores to slide the stabilized preforms from the ends of the cores. As the jaws are displaced, they separate to release their engagement with the preforms, so that the preforms may drop downwardly to be collected in a bin or on a conveyor.
While such devices operate efficiently, there is a need to provide a given injection molding apparatus with an optimal number of cores. This optimization previously has been limited by the physical requirements of the core and ejector components themselves, which limit the number of core and jaw combinations in a given area. Accordingly, there is a need for an apparatus which maximizes the number of cores for a given area on an injection molding machine.